<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="https://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script>
</head>
<body>
    <a href="" id="test-jquery">点我</a>
    <script>
        // 选择器就是css的选择器
        $('#test-jquery').click(function (){
            alert('hello');
        });
    </script>
</body>
</html>